Polymerization in aqueous media

ABSTRACT

A method for the solution or amulsion polymerization of ethylenically unsaturated monomers, styrene, and other free radical polymerizatable monomers in aqueous media in which a cobalt chain transfer agent is used which has both hydrolytic stability and solubility in water and in the organic phase with preferential solubility in the organic phase.

FIELD OF INVENTION

This invention relates to free-radical polymerization in emulsion or in aqueous solution to produce polymers with defined molecular weight and end group structures and to certain cobalt complexes employed in the polymerization process.

BACKGROUND ART

U.S. Pat. No. 5,324,879 discloses the use of cobalt(III) complexes to control molecular weights in free radical polymerization. U.S. Pat. No. 4,694,054 discloses the use of certain Co(II) complexes in emulsion polymerization.

SUMMARY OF THE INVENTION

This invention concerns a method for the solution or emulsion polymerization in aqueous media of at least one monomer selected from the group

a) 1,1-disubstituted ethylenically unsaturated monomer;

b) styrene;

c) a mixture of a and b; and

d) a mixture of at least one of a and b with one or more other free radical polymerizable monomers;

said monomer or monomer mixture comprising at least 50 percent by weight of monomer selected from at least one of a and b; comprising contacting the following materials:

i) water or a single phase water-organic solvent mixture,

ii) at least one monomer selected from a to d,

iii) a cobalt chelate chain transfer agent,

iv) an optional surfactant for emulsion polymerization,

v) an optional free radical initiator soluble in the media;

wherein the cobalt chelate chain transfer agent has the following properties:

vi) hydrolytic stability, and

vii) solubility in water and in the organic phase, with preferential solubility in the organic phase.

We have discovered that certain types of cobalt complexes are most effective in controlling the molecular weights in emulsion polymerization or in aqueous solution. These complexes act as efficient catalytic chain transfer agents and produce polymers with unsaturated chain ends. Either cobalt (II) complexes or cobalt (III) complexes can be utilized in the present invention. The reaction conditions are extremely important in determining the success of the experiment and must be chosen with regard to the complex used.

This invention provides a process whereby free radical polymerization can be readily carried out in aqueous or part aqueous media to produce macromonomers. Such macromonomers are oligomeric or homo- or copolymers containing unsaturation at a terminus. The macromonomers are of low color and have a high degree of terminal unsaturation. The process of the invention utilizes free radical polymerization in the presence of a metal complex which gives catalytic chain transfer and which in addition has ligands necessary to convey the necessary hydrolytic stability and solubility parameters. Complexes suitable for emulsion polymerization have solubility in both the organic and aqueous phases and partition in favor of the organic phase. Complexes suitable for aqueous solution polymerisation are soluble in water-monomer or water-monomer-cosolvent mixtures.

A list of preferred complexes is shown below. It will be obvious to those skilled in the art that any metal complex which gives catalytic chain transfer and which in addition has ligands necessary to convey the necessary hydrolytic stability and solubility parameters may be used in the present invention. Preferred complexes are those selected from square planar cobalt(II) and cobalt(III) chelates.

    ______________________________________                                          ##STR1##                                                                      Co(II)(DPGBF.sub.2).sub.2                                                                    Y = Z = Ph, L = ligand                                           CO(II)(DMGBF.sub.2).sub.2                                                                    Y = Z = Me, L = ligand                                           CO(II)(EMGBF.sub.2).sub.2                                                                    Y = Me, Z = Et, L = ligand                                       CO(II)(DEGBF.sub.2).sub.2                                                                    Y = Z = Et, L = ligand                                           CO(II)(CHGBF.sub.2).sub.2                                                                    Y + Z = (CH.sub.2).sub.4 -(cyclohexyl),                                        L = ligand.                                                       ##STR2##                                                                      RCo(III)(DPGBF.sub.2).sub.2                                                                  Y = Z = Ph, R = alkyl, L = ligand                                RCo(III)(DMGBF.sub.2).sub.2                                                                  Y = Z = Me, R = alkyl, L = ligand                                RCo(III)(EMGBF.sub.2).sub.2                                                                  Y = Me, Z = Et, R = alkyl, L = ligand                            RCo(III)(DEGBF.sub.2).sub.2                                                                  Y = Z = Et, R = alkyl, L = ligand                                RCo(III)(CHGBF.sub.2).sub.2                                                                  Y + Z = (CH.sub.2).sub.4 -(cyclohexyl),                                        R = alkyl, L = ligand                                            RCo(III)(DMGBF.sub.2).sub.2                                                                  Y = Z = Me, R = halogen, L = ligand.                             ______________________________________                                    

The cobalt (III) complexes based on BF₂ -bridged 3,4-hexandione dioxime, 2,3-pentandione dioxime and 1,2-cyclohexanedione dioxime ligands are designed to give improved stability and/or solubility parameters.

Cobalt(II) complexes for example, Co(II)(DMG-BF₂)₂ !, although effective in emulsion polymerization, have disadvantages when used directly because of their extreme sensitivity to air. It is, therefore, preferable to use cobalt(III) complexes for example, iPrCo(III)(DMG-BF₂)₂ ! which generate the active cobalt(II) species in situ under the reaction conditions. In the case of most alkyl cobalt (III) complexes this involves homolytic scission of the cobalt-R bond.

Other complexes that can be used include cobalt(III) complexes which are reduced to cobalt (II) complexes in a bimolecular process involving reaction with other species in the reaction medium for example, ClCo(III)(DMG-BF₂)₂ or MeCo(III)(DEG-BF₂)₂ !. Cobalt(III) complexes which are not as readily converted to cobalt (II) complexes for example MeCo(III)(DMG-BF₂)₂ ! are less effective in controlling molecular weight.

DETAILS OF THE INVENTION

To achieve best control over molecular weight, the ligands (L) are selected to suit the reaction conditions (monomers, cosolvents, surfactant, reaction temperature, etc.). L is selected from Lewis bases including tertiary amines (such as pyridine), water, ether, phosphines, and the like, as will be obvious to one skilled in the art. The use of the cobalt (II) complexes for example Co(II)(DMG-BF₂)₂ ! gives poor results with hydroxy and acid monomers for example HEMA or MAA!. The use of the corresponding cobalt(III) complexes, iPrCo(III)DMG-BF₂)₂ or MeCo(III)(DEG-BF₂)₂ !, which are compatible with hydroxy and acid monomers, gives good results.

The activity of the cobalt(III) complexes shows less dependence on surfactant type than is seen with cobalt(II) complexes. Depending on the reaction conditions cobalt(III) complexes are up to 3-20 fold more active than the corresponding cobalt(II) complexes in reducing molecular weight in emulsion polymerization. Although use of a surfactant (iv) may be desirable, such use is not necessary for self-stabilizing systems or systems otherwise stable such as by employment of block or graft copolymer stabilizers.

An important factor in controlling activity in emulsion polymerization is the solubility of the complex in aqueous and organic media. The complex should be soluble in both the organic and aqueous phases and the partition coefficient between the aqueous and organic phases should be in favor of the organic phase. Complexes based on diethyl glyoxime for example, iPrCo(III)(DEG-BF₂)₂ ! are more active than those based on dimethyl glyoxime for example, iPrCo(III)(DMG-BF₂)₂ !.

However, some water solubility is required for the complex to distribute through the reaction mixture. The diphenyl glyoxime complexes for example, Co(II)(DPG-BF₂)₂ and MeCo(III)(DPG-BF₂)₂ ! show much reduced activity with respect to corresponding dimethyl glyoxime complexes for example Co(II)(DMG-BF₂)₂ and iPrCo(III)(DMG-BF₂)₂ !.

Higher complex concentrations are required for molecular weight control with very hydrophobic monomers, for example BMA or styrene. This result is most likely due to the lower solubility of the complex in the organic phase. Use of the term "styrene" herein is intended to include substituted styrenes as well.

Another important factor is the stability of the complex to hydrolysis. Incremental addition of the complex during the reaction improves molecular weight control especially in polymerizations of acid monomers (e.g. MAA) or with acidic reaction conditions. For both cobalt(II) and cobalt(III) glyoxime complexes, BF₂ -bridging improves the hydrolytic stability of the complexes. The use of lower reaction temperatures is also advantageous.

Water soluble azo-compounds, for example 4,4'-azobis(cyanovaleric acid), are the preferred initiators for emulsion polymerization and for aqueous solution polymerization. Faster decomposing azo compounds, for example, WAKO V-44 2,2'-azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride!, allow use of lower reaction temperatures (50°-60° C.) and are preferred for polymerizations involving methacrylic acid. Organic soluble azo-compounds can also be used for emulsion polymerization in some cases.

The preferred monomers for use with this invention are a-methylvinyl and styrenic monomers, mixtures of these monomers and mixtures of these monomers with other unsaturated monomers including acrylic monomers. The preferred a-methylvinyl monomers include: alkyl methacrylates (e.g. MMA, EMA, n-BMA, t-BMA, 2-EA, PHMA, etc.) substituted alkyl methacrylates (e.g. HEMA, GMA, etc.), methacrylic acid (e.g. MAA), etc.

In emulsion polymerization, a wide range of surfactants and surfactant concentrations have been used in conjunction with cobalt(III) complexes. Both ionic and non-ionic surfactants may be employed. These surfactants include SDS, ADS, AerosolMA, Teric N40, Teric NX40L, alkanate, AerosolOT/Teric N40 and similar surfactants. These surfactants may be used alone or in combination. ##STR3##

This invention will lead to polymers with a high degree of terminal unsaturation (typically in excess of 90%). Polymers formed with a-methyl vinyl monomers (CH₂ ═C(CH₃)X) will have the following end-group structure. ##STR4##

The products can thus be used as macromonomers in a wide variety of applications. The end group functionality of the low molecular weight methacrylate ester polymers formed by the processes described can be established quantitatively by NMR spectroscopy or by thermogravimetric analysis. Some typical results are as follows. Within experimental error, there is one unsaturated end group per molecule.

                  TABLE 1                                                          ______________________________________                                         End Group Functionality in Macromonomers                                       Macromonomer                                                                             complex.sup.a M.sub.n.sup.b                                                                         end groups/molecule.sup.c                       ______________________________________                                         MMA       iPrCo(III)(DMG-BF.sub.2).sub.2                                                               1400   1.04                                            MMA       MeCo(III)(EMG-BF.sub.2).sub.2                                                                2100   0.98                                            MMA       MeCo(III)(DEG-BF.sub.2).sub.2                                                                2400   0.98                                            HEMA      iPrCo(III)(DMG-BF.sub.2).sub.2                                                               810    0.97                                            ______________________________________                                          .sup.a cobalt complex used in macromonomer synthesis.                          .sup.b GPC number average molecular weight.                                    .sup.c unsaturated chain end as estimated by NMR.                        

Some of general advantages of polymerisation in emulsion and aqueous solution polymerisation is organic solutions have been delineated above. A further unexpected and important advantage of forming macromonomers in aqueous or part-aqueous media is that the products have substantially less color than those formed in organic media. Color is extremely important in many applications, for example, clear and light colored coatings and other materials.

Illustrative of the invention are the following examples showing the dependence of molecular weight on the type of complex, surfactant and comonomers employed; application to copolymer synthesis; and aqueous solution polymerisation of methacrylic acid and 2-hydroxyethyl methacrylate.

    ______________________________________                                         Key                                                                            ______________________________________                                         MMA             methyl methacrylate                                            HEMA            hydroxyethyl methacrylate                                      nBMA            n-butyl methacrylate                                           tBMA            t-butyl methacrylate                                           PhMA            phenyl methacrylate                                            2-EHMA          2-ethylhexyl methacrylate                                      MAA             methacrylic acid                                               MAm             methacrylamide                                                 GMA             glycidyl methacrylate                                          ______________________________________                                    

EXAMPLES 1-10

Emulsion polymerization with cobalt (II) complexes

    ______________________________________                                         Initial Charge:                                                                Solution 1:                                                                               Water            733     g                                                     Surfactant solution (30% w/v)                                                                   10.14   g                                                     4,4'-azobis(cyanovaleric acid)                                                                  1.32    g                                          Solution 2:                                                                               cobalt(II) complex                                                                              x       ppm                                                   MMA              35.2    g                                          Solution3: MMA              317     g                                          Solution4: Water            90      g                                                     Surfactant solution (30% w/v)                                                                   10.98   g                                          ______________________________________                                    

Solution 1 was degassed over 30 minutes and heated to 80° C. when solution 2 and 10% of solution 4 was added in one shot. Solution 3 and the remaining solution 4 were then added over 90 min. The reaction temperature was then held for a further 90 min. The results of this and similar experiments are summarized in Table

                                      TABLE 2                                      __________________________________________________________________________     Effect of Complex, Surfactant and Initiator, Cobalt (II) Complexes                        Conc                    Particle                                    Example                                                                             Complex                                                                              (ppm)                                                                              Initiator                                                                             M.sub.n                                                                            M.sub.W /M.sub.n                                                                   Surfactant                                                                          size                                        __________________________________________________________________________          none  0   0.27% V5010                                                                           177100                                                                             2.1 1.4% ADS                                                                            99                                          1    Co(II)DPG                                                                            50  0.27% V5010                                                                           151000                                                                             2.2 1.4% ADS                                                                            87                                          2    Co(II)DMG                                                                            5   0.27% V5010                                                                           192600                                                                             2.1 1.4% ADS                                                                            93                                          3          50  0.27% V5010                                                                           171400                                                                             1.8 1.4% ADS                                                                            95                                          4    Co(II)DPG                                                                            50  0.27% V5010                                                                           179000                                                                             2.3 1.4% SDS                                                                            80                                          5    Co(II)DMG                                                                            50  0.27% 5010                                                                            20000                                                                              : 1.8                                                                              1.4% SDS                                                                            281                                         6          100 0.27% V5010                                                                           16100                                                                              2.5 1.4% SDS                                                                            407                                              none  0   0.1% V5010                                                                            585600                                                                             2.3 1.4% SDS                                                                            115                                         7    Co(II)DMG                                                                            50  0.1% V5010                                                                            70600                                                                              2.4 1.4% SDS                                                                            322                                              none  0   0.1% V5010                                                                            452500                                                                             2.1 6% SDS                                                                              68                                          8    Co(II)DMG                                                                            50  0.1% V5010                                                                            48200                                                                              2.1 6% SDS                                                                              206                                         9    Co(II)DMG                                                                            100 0.1% V5010                                                                            38400                                                                              2.6 6% SDS                                                                              276                                              none  0   0.1% APS                                                                              132152                                                                             3.3 1.4% SDS                                                                            148                                         10   Co(II)DMG                                                                            50  0.1% APS                                                                              64768                                                                              1.7 1.4% SDS                                                                            118                                         __________________________________________________________________________      .sup.a initiators: APS ammonium persulphate; V5010 4,4azobis(cyanovaleric      acid)                                                                    

EXAMPLES 11-33

Emulsion polymerization with cobalt (IU) complexes (with surfactant feed)

    ______________________________________                                         Solution 1:                                                                               Water            75      g                                                     Surfactant solution (10% w/v)                                                                   3       g                                                     4,4'-azobis(cyanovaleric acid)                                                                  140     mg                                         Solution 2:                                                                               Surfactant solution (10% w/v)                                                                   1       g                                                     iPrCo(III)(DMG-BF.sub.2).sub.2                                                                  1.96    mg                                                    MMA              3.5     g                                          Solution 3:                                                                               MMA              31.2    g                                          Solution 4:                                                                               Surfactant solution (10% w/v)                                                                   8       g                                          ______________________________________                                    

Solution 1 was degassed over 20 minutes and heated to 80° C. when solution 2 was added in one shot. The feeds (solution 3 and 4) were commenced and added over 90 min. The reaction temperature was then increased to 85° C. and heating and stirring continued for a further 90 min. Results of this and similar experiments are summarized in Tables 3-5.

                                      TABLE 3                                      __________________________________________________________________________     Effect of Complex on Emulsion Polymerisation of MMA.sup.a                                       conc        %   %                                             Example                                                                             Complex     ppm M.sub.n                                                                            M.sub.w /M.sub.n                                                                   Conv                                                                               coagulum                                      __________________________________________________________________________          none        0   181000                                                                             2.5 100 --                                            11   Co(II)(DMG-BF.sub.2).sub.2                                                                 14  29900                                                                              2.4 95  5                                             12   iPrCo(III)(DMG-BF.sub.2).sub.2                                                             17  10000                                                                              2.2 100 4                                             13   2-octyl Co(III)(DMG-BF.sub.2).sub.2                                                        18  6200                                                                               17  34  4                                             14   iPrCo(II)(CHG-BF.sub.2).sub.2                                                              16  18600                                                                              2.1 100 3                                             15   MeCo(III)(EMG-BF.sub.2).sub.2                                                              16  6200                                                                               1.9 91  4                                             16   MeCo(III)(DEG-BF.sub.2).sub.2                                                              16  3200                                                                               1.6 93  6                                             17   Co(II)(DPG-BF.sub.2).sub.2                                                                 22  119200                                                                             2.5 72  1                                             18   EtCo(III)(DPG-BF.sub.2).sub.2                                                              24  30600                                                                              1.9 92  5                                             __________________________________________________________________________      .sup.a 1% (w/v) SDS surfactant                                           

                                      TABLE 4                                      __________________________________________________________________________     Effect of Surfactant on Emulsion Polymerization of MMA.sup.a                                               %   %                                              Example                                                                             Surfactant wt %.sup.b                                                                         M.sub.n                                                                            M.sub.w /M.sub.n                                                                   Conv'.sup.d                                                                        coagulum                                       __________________________________________________________________________     19   SDS        0.1 14200                                                                              2.5 100 11                                             20   SDS        0.5 10600                                                                              3.2 92  4                                              21   SDS        1.0 10000                                                                              2.1 100 4                                              22   SDS        3.0 8100                                                                               1.0 100 14                                             23   SDS        1.0 16000                                                                              2.2 62  2                                              24   Aerosol MA80                                                                              1.0 13100                                                                              2.0 80  13                                             25   SDS/Teric N40                                                                             0.1 11200                                                                              2.9 100 6                                              26   SDS/Teric NX40L                                                                           0.1 12300                                                                              2.5 100 17                                             27   alkanate   0.1 21000                                                                              2.0 88  13                                             28   AerosolOT/Teric N40                                                                       0.1 12700                                                                              2.0 92  16                                             29   AerosolOT/Teric NX40L                                                                     0.1 29800                                                                              2.2 91  12                                             __________________________________________________________________________      .sup.a iPrCo(III)(DMGBF.sub.2).sub.2 concentration 19 ppm.                     .sup.b Surfactant level                                                  

                  TABLE 5                                                          ______________________________________                                         Effect of Comonomers on Emulsion Polymerization of MMA                         Ex-                                       %                                    ample Comonomers       ratio  M.sub.n                                                                              M.sub.w /M.sub.n                                                                     Conv                                 ______________________________________                                               none.sup.a       --     10000 --    100                                  30    HEMA.sup.a,c     8:1    10600 2.0   75                                   31    HEMA.sup.b,c     8:1    19000 3.0                                        32    MAA.sup.b        8:1    17600 2.6   90                                   33    n-BMA:2-         .sup.d 8500  2.2   90                                         EHMA:MAA:HEMA:MAm.sup.a                                                  ______________________________________                                          .sup.a 1% (w/v) SDS surfactant, iPrCo(III)(DMGBF.sub.2).sub.2                  concentration 17 ppm.                                                          .sup.b 1% (wlv) SDS surfactant, iPrCo(III)(CHGBF.sub.2).sub.2                  concentration 17 ppm.                                                          .sup.c control (no complex) gave M.sub.n 119500, M.sub.w /M.sub.n 6.9.         .sup.d ratio of monomers was 10:1:1:20:1                                 

EXAMPLES 34-49

Emulsion polymerisation recipe (no surfactant feed)

    ______________________________________                                         Initial Charge:                                                                Solution 1: Water            75      g                                                     SDS solution (10% w/v)                                                                          3       g                                                     4,4'-azobis(cyanovaleric acid)                                                                  140     mg                                        Solution 2: iPrCo(III)(DMG-BF.sub.2).sub.2                                                                  2       mg                                                    MMA              3.5     g                                         Feed:       MMA              31.7    g                                         ______________________________________                                    

Water was degassed over 20 minutes and heated to 80° C. when solution 2 was added in one shot. The MMA feed was then added over 90 min. The reaction temperature was then increased to 85° C. and heating and stirring continued for a further 90 min. Results are summarized in Tables 6 and 7.

                  TABLE 6                                                          ______________________________________                                         Emulsion Polymerisations of MMA - dialkylglyoxime based complexes.sup.a        Ex-                  conc.                                                     ample Complex        ppm    M.sub.n                                                                              M.sub.w /M.sub.n                                                                     % Conv.                                ______________________________________                                         34    iPrCo(III)(DMG-BF.sub.2).sub.2                                                                19     13400 3.68  100                                    35                   190    1400  3.03  83                                     36    MeCo(III)(EMG-BF.sub.2).sub.2                                                                 19     4300  1.87  100                                    37                   45.sup.b                                                                              2100  1.69  94                                     38    MeCo(III)(DEG-BF.sub.2).sub.2                                                                 19     2900  1.58  69                                     39                   57     920   1.65  51                                     40                   49.sup.b                                                                              730   1.70  82                                     41                   48.sup.b                                                                              900   1.78  90                                     42    MeCo(III)(DMG-BF.sub.2).sub.2                                                                 46.sup.b                                                                              13700 2.65  100                                    43                          14700 2.55  100                                    ______________________________________                                          .sup.a 1% (w/v) SDS surfactant.                                                .sup.b 30% of total complex added in MMA feed.                           

                                      TABLE 7                                      __________________________________________________________________________     Emulsion Polymerisation of Other Monomers.sup.a                                Example                                                                             Monomer                                                                             Complex   conc. ppm                                                                           M.sub.n                                                                            M.sub.w /M.sub.n                                                                   % Conv                                        __________________________________________________________________________     44   n-BMA                                                                               iPrCo(III)(DMG-BF.sub.2).sub.2                                                           48   9800                                                                               1.8 98                                            45   n-BMA                                                                               MeCo(III)(DEG-BF.sub.2).sub.2                                                            48   5200                                                                               2.5 97                                            46   n-BMA                                                                               MeCo(III)(EMG-BF.sub.2).sub.2                                                            48   9400                                                                               2.5 100                                           47   t-BMA                                                                               MeCo(III)(DEG-BF.sub.2).sub.2                                                            43   3700                                                                               2.0 100                                           48   PhMA MeCo(III)(DEG-BF.sub.2).sub.2                                                            43   18000                                                                              2.3 100                                           49   GMA  iPrCo(III)(DMG-BF.sub.2).sub.2                                                           109  3500                                                                               1.8 90                                            __________________________________________________________________________      .sup.a 30% of complex added with monomer feed, 1% (w/v) SDS surfactant.  

EXAMPLES 50-51

    ______________________________________                                         Preparation of Styrene                                                         ______________________________________                                         Initial Charge:                                                                distilled water          75.03   g                                             Initiator (azobiscyanopentanoic acid)                                                                   0.1440  g                                             Surfactant (10% aq. soln of sodium dodecyl sulfate)                                                     3.14    g                                             Styrene                  3.59    g                                             MeCo(III)(DEG-BF.sub.2).sub.2                                                                           0.0031  g                                             Acetone                  0.5     mL                                            (Complex was dissolved in acetone)                                             Feed 1 (180 min @ 0.200 mL/min)                                                Styrene                  33.01   g                                             MeCo(III)(DEG-BF.sub.2).sub.2                                                                           0.0121  g                                             Acetone                  1.0     mL                                            (Complex was dissolved in acetone)                                             Feed 2 (90 min @ 0.089 mL/min)                                                 Initiator (azobiscyanopentanoic acid)                                                                   0.0690  g                                             Surfactant (10% aq. soln of SDS)                                                                        8.12    g                                             (This solution was prepared by gently                                          warming to 60° C.)                                                      ______________________________________                                    

Water was charged to a 5 neck, 250 mL reactor fitted with stirrer (400 rpm), condenser and thermocouple under a blanket of nitrogen. Initiator and surfactant were added to the reactor as single shots and heated to 80° C. When the reactor reached 80° C., the cobalt and styrene were added as single shots and Feed 1 commenced over 180 min. Some of the cobalt precipitated out of the monomer feed. Feed 2 (containing initiator/surfactant) was started 30 min after the start of polymerisation. The reactor was maintained at 80° C. for 90 min after the completion of the monomer feed, then cooled. The reactor was sampled at 30 min intervals to monitor molecular weight and conversion. Yield: 105.3 g stable white latex+small amount (<0.2 g) yellow coagulum

                  TABLE 8                                                          ______________________________________                                         Emulsion Polymerization of Styrene                                             Ex-                                                                            am-  Mono-                  conc.      M.sub.w /                                                                           %                                  ple  mer     Complex        ppm  M.sub.n                                                                              M.sub.n                                                                             Conv                               ______________________________________                                              Styrene none (control) --   130500                                                                               2.7  93                                 50   Styrene MeCo(III)(DEG-BF.sub.2).sub.2                                                                 127  44000 3.2  94                                 51   Styrene MeCo(III)(DMG-BF.sub.2).sub.2                                                                 127  48000 4.8  97                                 ______________________________________                                    

EXAMPLE 52

Preparation of 60:40 MAA/MMA Macromonomer

    ______________________________________                                         Initial Charge:                                                                             Deionised Water                                                                              150       g                                         Solution 1   Antrox CA897  0.6       g                                                      Antrox CO436  0.3       g                                                      Initiator WAKO V-44                                                                          0.4       g                                                      iPrCo(III)(DMG-BF.sub.2).sub.2                                                               8         mg                                                     MMA           4         g                                         Solution 2:  iPrCo(III)(DMG-BF.sub.2).sub.2                                                               16        mg                                                     MMA           44.8      g                                         Solution 3:  MAA           28.0      g                                         ______________________________________                                    

Water (150 mL) was degassed for 20 minutes with a nitrogen purge and heated to 58° C. Solution 1 was added in one shot. The feeds (solutions 2 and 3) were then added over 60 minutes. That rate of feed two was such that 5 g was added over the first 20 min, 10 g over the second 20 min, and the remainder over the third 20 min. The reaction was held at 58° C. for 30 minutes then heated to 65° C. for 1 hour and cooled. Conversion>95%, GPC molecular weight M_(n) 920, M_(w) /M_(n) 1.6.

EXAMPLES 53-58

Preparation of BMA/HEMA/MA copolymer

    ______________________________________                                         Initial Charge                                                                              Water             75     g                                                     SDS (10% solution)                                                                               3      g                                                     4,4'-azobis(cyanovaleric acid)                                                                   141    mg                                       Solution 1:  MeCo(III)(EMG-BF.sub.2).sub.2                                                                    3.00   mg                                                    MMA               0.098  g                                                     MAA               0.62   g                                                     BMA               2.13   g                                                     HEMA              1.48   g                                        Solution 2:  MMA               0.562  g                                                     BMA               12.02  g                                                     MeCo(III)(EMG-BF.sub.2).sub.2                                                                    2.00   mg                                       Solution 3:  MAA               7.76   g                                                     HEMA              8.45   g                                        ______________________________________                                    

The initial charge was degassed for 30 minutes with a nitrogen purge and heated to 80° C. with a preheated water bath. Solution I was added in one shot. Solutions 2 and 3 were then added simultaneously over 90 min. On completion of the feeds, the temperature was increased to 85° C. and held for 90 min. The results of this and similar experiments are summarized in Table 9.

                  TABLE 9                                                          ______________________________________                                         Emulsion Copolymerization of MMA/MAA/BMA/HEMA                                  Ex-                                                                            am-                                                                            ple  Complex       ppm    M.sub.n                                                                             M.sub.w                                                                              M.sub.w /M.sub.n                                                                     Conv.                               ______________________________________                                         53   iPrCo(III)(DMG-BF.sub.2).sub.2                                                               130.sup.a                                                                             5900 17600 2.97  100%                                54   iPrCo(III)(DMG-BF.sub.2).sub.2                                                               80.sup.b                                                                              2900 3700  1.29  100%                                55   MeCo(III)(EMG-BF.sub.2).sub.2                                                                110.sup.b                                                                             4000 11400 2.85  96%                                 56   MeCo(III)(EMG-BF.sub.2).sub.2                                                                50.sup.a                                                                              4900 12600 2.53  100%                                57   MeCo(III)(DEG-BF.sub.2).sub.2                                                                111.sup.b                                                                             830  1500  1.74  96%                                 58   MeCo(III)(DEG-BF.sub.2).sub.2                                                                80.sup.a                                                                              2300 3200  1.44  100%                                ______________________________________                                          .sup.a All complex in solution 1.                                              .sup.b 40% of total complex added with Feed 1.                           

EXAMPLES 59-62

Preparation of GMA-MMA macromonomer

    ______________________________________                                         Initial charge:                                                                distilled water         75     g                                               SLS (3% solution)       5      g                                               Solution 1:                                                                    4,4'-azobis(cyanovaleric acid)                                                                         140    mg                                              GMA                     2.6    g                                               MMA                     1.0    g                                               MeCo(III)(DEG-BF.sub.2).sub.2                                                                          8.9    mg                                              Feed:                                                                          GMA                     18     g                                               MMA                     13.5   g                                               MeCO(III)(DEG-BF.sub.2).sub.2                                                                          7.9    mg                                              ______________________________________                                    

The water-SLS mixture was vacuum degassed for 30 minutes and placed 5-neck, reactor fitted with a stirrer, condenser and a thermocouple under a blanket of nitrogen and heated to 80° C. Solution 1 was then added and the Feed commenced immediately and added over 90 minutes. The reactor was maintained at 80° C. for a further 90 minutes. Conversion based on % solids was>90%.

                  TABLE 10                                                         ______________________________________                                         Emulsion Copolymerization of MMA and GMA                                       Example Complex         ppm     M.sub.n                                                                              M.sub.w /M.sub.n                         ______________________________________                                         59      iPrCo(III)(DMG-BF.sub.2).sub.2.sup.a                                                           213     790   2.04                                     60      IPrCo(III)(DMG-BF.sub.2).sub.2.sup.a                                                           135     2900  1.51                                     61      iPrCo(III)(DMG-BF.sub.2).sub.2                                                                 100     3620  2.13                                     62      MeCo(III)(DEG-BF.sub.2).sub.2                                                                  146     1460  1.55                                     ______________________________________                                          .sup.a Latex unstable                                                    

EXAMPLE 63

Aqueous Solution polymerization of MAA

    ______________________________________                                         Initial Charge:                                                                distilled water        150    g                                                Initiator (WAKO VA-044)                                                                               0.3    g                                                water                  2      mL                                               iPrCo(III)(DMG-BF.sub.2).sub.2                                                                        13     mg                                               acetone                2      mL                                               Feed:                                                                          methacrylic acid       74     g                                                iPrCo(III)(DMG-BF.sub.2).sub.2                                                                        7.5    mg                                               ______________________________________                                    

Water (150 mL) was charged to a 5 neck, 500 mL reactor fitted with stirrer (300 rpm), condenser and thermocouple under a blanket of nitrogen and heated to 55° C. Initiator (0.3 g dissolved in 2 mL water) and iPrCo(III)(DMG-BF₂)₂ (13 mg dissolved in 2 mL acetone) were added to the reactor as single shots. The feed of MAA containing the remaining iPrCo(III)(DMG-BF₂)₂) was commenced immediately (1.23 mL/min over 60 min). The reactor was maintained at 55° C. for 30 min after the completion of the feed, then cooled. The methacrylic acid macromonomer was isolated by evaporation of the water.

Conversion: approx. 90%, NMR analysis indicates number average molecular weight of about 1000.

EXAMPLES 64-72

Aqueous Solution polymerization of HEMA

The color of the product is dramatically lighter than similar macromonomers prepared in organic solvents (e.g., isopropanol). Complex activity is also higher.

    ______________________________________                                         Initial Charge:                                                                distilled water    52     g                                                    methanol           23     g                                                    Solution 1:                                                                    4,4'-azobis(cyanovaleric acid)                                                                    140    g                                                    iPrCo(III)(DMG-BF.sub.2).sub.2                                                                    10     mg in 3.5 g HEMA                                     Solution 2:                                                                    HEMA               31.7   g                                                    iPrCo(III)(DMG-BF.sub.2).sub.2                                                                    7      mg                                                   ______________________________________                                    

The water-methanol mixture was charged to a 5 neck, 500 mL reactor fitted with stirrer (300 rpm), condenser and thermocouple under a blanket of nitrogen and heated to 80° C. The initiator (0.14 g dissolved in 3.5 mL HEMA) and iPrCo(III)(DMG-BF₂)₂ were added to the reactor as a single shot. The feed of HEMA containing the remaining iPrCo(III)(DMG-BF₂)₂) was commenced immediately and added over 90 min. The reactor was maintained at 80° C. for 150 min after the completion of the feed. Further aliquots of the initiator (70 mg) were added at 1 hourly intervals. The results of these experiments are sumarized in Table 11.

                                      TABLE 11                                     __________________________________________________________________________     Aqueous Solution Polymerization of HEMA                                                       %              %                                                Example                                                                             Complex   solids                                                                            ppm                                                                               solvent                                                                              M.sub.n.sup.a                                                                     Conv                                                                               Colour                                       __________________________________________________________________________     64   MeCo(III)(DEG-BF.sub.2).sub.2                                                            30 56.sup.a                                                                          water 3180                                                                              93  cloudy yellow                                65   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 56.sup.a                                                                          water 1470                                                                              87  pale yellow                                  66   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 171.sup.a                                                                         water 990                                                                               68  pale yellow                                  67   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           40 343                                                                               water 530                                                                               72  pale orange                                  68   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           50 400                                                                               water 490                                                                               72  pale orange                                  69   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 162                                                                               isopropanol                                                                          420                                                                               37  dark brown                                   70   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 160                                                                               70:30 water -                                                                        590                                                                               30  brown                                                             isopropanol                                               71   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 105                                                                               70:30 water -                                                                        1610                                                                              98  pale yellow                                                       methanol                                                  72   iPrCo(III)(DMG-BF.sub.2).sub.2                                                           30 162                                                                               70:30 water -                                                                        810                                                                               68  pale yellow                                                       methanol                                                  __________________________________________________________________________      .sup.a number average molecular weight estimated by NMR determination of       the unsaturate end groups                                                

GENERAL PROCEDURE FOR PREPARATION OF COBALT(III) CATALYSTS

Preparation of bis m- (2,3-hexanedione dioximato)(2-)-O:O'!! tetrafluorodiborato (2-)-N,N',N",N'"! (methyl) (aqua) cobalt

Cobalt(III) complexes of the invention and all such complexes useful in the disclosed process are made by appropriate compound substitutions in the procedure described in Paragraph A hereafter. The same is true for Cobalt(II) complexes of the invention and of utility generally in the disclosed process. One skilled in the art will have no difficulty, given the disclosure that has been provided, in making all such complexes and in pairing the appropriate Lewis base(s) and cobalt-containing moieties to obtain the claimed cobalt complexes and to obtain the fruits of the claimed process.

A. Preparation of Methyl pyridinato-Co(III)-DEG

    ______________________________________                                                    Methanol       50         mL                                                   3,4-hexanedione dioxime                                                                       3.0        g                                                    CoCl.sub.2.6H.sub.2 O                                                                         2.0171     g                                         Solution 1:                                                                               Sodium hydroxide                                                                              0.819      g                                                    Water          0.819      g                                                    Pyridine       0.670      mL                                        Solution 2:                                                                               Sodium hydroxide                                                                              0.532      g                                                    Water          0.532      g                                                    Sodium borohydride                                                                            0.365      g                                                    Methyl bromide 0.590      mL                                        ______________________________________                                    

The methanol was degassed under nitrogen for 20 minutes at room temperature and the COCl₂.6H₂ O and the 3,4-hexanedione dioxime were added. After ten minutes the Solution 1 was added, followed by slow addition of pyridine. The reaction mixture was cooled to -20° C. and stirring under nitrogen was continued for 20 minutes. The second sodium hydroxide solution and the sodium borohydride were added slowly. Methyl bromide was added dropwise over 20 minutes and the reaction mixture was allowed to reach room temperature. Half of the solvent was removed by evaporation and 40 mL of cold water was added. The compound was filtered and washed with a pyridine-water (5%) solution, and dried over P₂ O₅.

B: Preparation of Methyl pyridinato-Co(III)-DEG BF₂ Bridged.

    ______________________________________                                         Methyl pyridinato-Co(III)-DEG                                                                     3.551        g                                              BF.sub.3 Et.sub.2 O                                                                               9.217        g                                              Ether              5            mL                                             ______________________________________                                    

The boron triethyletherate and ether were cooled under nitrogen at -20° C. for 40 minutes. The methyl pyridinato-Co(III)-DEG was added over 20 minutes. The reaction was allowed to reach room temperature, then the compound was isolated by filtration and washed with ether.

C: Preparation of Methyl aqua-Co(III)-DEG BF₂ Bridged.

    ______________________________________                                         Methyl pyridinato-Co(III)-DEG BF.sub.2 bridged                                                        3.178      g                                            Water                  30         mL                                           ______________________________________                                    

The water was degassed under nitrogen at 30° C. for 10 minutes. The methyl pyridinato-Co(III)-DEG BF₂ Bridged complex was added and the solution held at 30° C. for 40 minutes. The solution was allowed to reach room temperature and the compound was isolated by filtration, and washed with water.

PROCEDURE FOR PREPARING COBALT(II) CATALYSTS

The Co(II) cobaloximes are prepared as are the Co(III) materials described above without the reaction of the intermediate with alkyl bromide, by reacting the appropriate dioxime with cobaltous chloride and bridging the reaction product with BF₃ etherate. 

We claim:
 1. A method for preparing macromonomers by free-radical polymerization in aqueous media of at least one monomer selected from the groupa) 1,1-disubstituted ethylenically unsaturated monomer; b) styrene; c) a mixture of a and b; and d) a mixture of at least one of a and b with one or more other free radical polymerizable monomers; said monomer or monomer mixture comprising at least 50 percent by weight of monomer selected from at least one of a and b; comprising contacting the following materials: i) water or a single phase water-organic solvent mixture, ii) at least one monomer selected from a to d, iii) an optional surfactant for emulsion polymerization, iv) an optional free-radical initiator soluble in the media; v) a cobalt III chelate chain transfer agent having the following properties: vi) hydrolytic stability, and vii) solubility in water and in the organic phase, with preferential solubility in the organic phase.
 2. A method according to claim 1 comprising emulsion polymerization employing water (i) and surfactant (iii).
 3. A method according to claim 1 comprising solution polymerization employing no surfactant (iii) wherein the cobalt chelate is soluble in the water or single phase water-organic solvent.
 4. A method according to claim 1 wherein the cobalt chelate chain transfer agent is selected from at least one member of the group

    ______________________________________                                          ##STR5##                                                                      RCo(III)(DPGBF.sub.2).sub.2                                                                 Y = Z  Ph, R = alkyl, L = Lewis base                              RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me, R = alkyl, L = Lewis base                             RCo(III)(EMGBF.sub.2).sub.2                                                                 Y = Me, Z = Et, R = alkyl, L = Lewis base                         RCo(III)(DEGBF.sub.2).sub.2                                                                 Y = Z = Et, R = alkyl, L = Lewis base                             RCo(III)(CHGBF.sub.2).sub.2                                                                 Y + Z = (CH.sub.2).sub.4 , R = alkyl,                                          L = Lewis base and                                                RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me, R = halogen, L = Lewis base.                          ______________________________________                                    


5. A method according to claim 2 wherein the cobalt chelate chain transfer agent is selected from at least one member of the group

    ______________________________________                                          ##STR6##                                                                      RCo(III)(DPGBF.sub.2).sub.2                                                                 Y = Z = Ph, R = alkyl, L = Lewis base                             RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me, R = alkyl, L = Lewis base                             RCo(III)(EMGBF.sub.2).sub.2                                                                 Y = Me, Z  Et, R = alkyl, L = Lewis base                          RCo(III)(DEGBF.sub.2).sub.2                                                                 Y = Z = Et, R = alkyl, L = Lewis base                             RCo(III)(CHGBF.sub.2).sub.2                                                                 Y + Z = (CH.sub.2).sub.4 , R = alkyl,                                          L = Lewis base and                                                RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me; R = halogen, L = Lewis base.                          ______________________________________                                    


6. A method according to claim 3 wherein the cobalt chelate chain transfer agent is selected from at least one member of the group

    ______________________________________                                          ##STR7##                                                                      RCo(III)(DPGBF.sub.2).sub.2                                                                 Y = Z = Ph, R = alkyl, L = Lewis base                             RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me, R = alkyl, L = Lewis base                             RCo(III)(EMGBF.sub.2).sub.2                                                                 Y = Me, Z  Et, R = alkyl, L = Lewis base                          RCo(III)(DEGBF.sub.2).sub.2                                                                 Y = Z = Et, R = alkyl, L = Lewis base                             RCo(III)(CHGBF.sub.2).sub.2                                                                 Y + Z = (CH.sub.2).sub.4 , R = alkyl,                                          L = Lewis base and                                                RCo(III)(DMGBF.sub.2).sub.2                                                                 Y = Z = Me; R = halogen, L = Lewis base.                          ______________________________________                                    


7. A method according to claim 4 wherein the cobalt chelate chain transfer agent is alkylCo(III) (dimethyl glyoxime-BF₂)₂.
 8. A method according to claim 4 wherein the cobalt chelate chain transfer agent is alkylCo(III) (diethyl glyoxime-BF₂)₂.
 9. A method according to claim 7 wherein the alkyl is isopropyl.
 10. A method according to claim 8 wherein the alkyl is isopropyl.
 11. A cobalt chelate chain transfer agent selected from the group:

    ______________________________________                                          ##STR8##                                                                      RCo(III)(EMGBF.sub.2).sub.2                                                                 Y = Me, Z = Et, R = alkyl, L = Lewis base;                        RCo(III)(DEGBF.sub.2).sub.2                                                                 Y = Z = Et, R = alkyl, L = Lewis base; and                        RCo(III)(CHGBF.sub.2).sub.2                                                                 Y + Z = (CH.sub.2).sub.4 , R = alkyl,                                          L = Lewis base.                                                   ______________________________________                                     